224 research outputs found
In-medium Effects in the Eta-Photoproduction through the Resonance with the Relativistic Approach
In-medium effects in photon excitation of the S resonance from nucleon
and its decay to -meson using the RMF approach is studied. We examine the
in-medium effects by varing the Dirac fields of the nucleon and the S
resonance separately. We obtained a conclusion that the Dirac fields of the
nucleon, which reduces the nucleon effective mass, enlarge the width of
S resonance, and small Dirac-fields of the resonance shifts the peak
position, and these combined effects can explain the in-medium properties
observed in the experimental data for C(,) reaction.Comment: 10 pages and 3 figure
On the IMF Multiplicity in Au+Au Reactions
Intermediate mass fragment (IMF) multiplicity has been investigated for Au+Au
reactions at incident energies of 100, 250 and 400 MeV/A. From the analysis of
the impact-parameter-dependence of the IMF multiplicity using our QMD plus
statistical evaporation model, we found that 1) statistical decay process
modifies the results greatly, and 2) the Fermi motion plays a role to increase
the IMF multiplicity for whole impact-parameter range.Comment: 9pages, Latex is used, 2 Postscript figures are available by request
from [email protected]
Role of the Landau-Migdal Parameters with the Pseudovector and the Tensor Coupling in Relativistic Nuclear Models -- The Quenching of the Gamow-Teller Strength --
Role of the Landau-Migdal parameters with the pseudovector () and the
tensor coupling () is examined for the giant Gamow-Teller (GT) states in
the relativistic random phase approximation (RPA). The excitation energy is
dominated by both and in a similar way, while the GT strength is
independent of and in the RPA of the nucleon space, and is
quenched, compared with that in non-relativistic one. The coupling of the
particle-hole states with nucleon-antinucleon states is expected to quench the
GT strength further through .Comment: 7 pages, ReVTe
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